stratisd

A daemon that manages a pool of block devices to create flexible filesystems.

Background

Stratis (which includes stratisd as well as stratis-cli), provides ZFS/Btrfs-style features by integrating layers of existing technology: Linux's devicemapper subsystem, and the XFS filesystem. stratisd manages collections of block devices, and exports a D-Bus API. Stratis-cli's stratis provides a command-line tool which itself uses the D-Bus API to communicate with stratisd.

Website

See https://stratis-storage.github.io/.

Getting involved

Communication channels

If you have questions, please don't hesitate to ask them, either on the mailing list or IRC.

Mailing list

Development mailing list: stratis-devel@lists.fedorahosted.org, -- subscribe here.

IRC

irc.libera.chat #stratis-storage.

For Developers

Stratisd is written in Rust, which helps the implementation be small, correct, and avoid requiring shipping with a large language runtime.

Issue tracking and Development

Stratisd development uses GitHub issue tracking, and new development occurs via GitHub pull requests (PRs). Patches or bug reports may also be sent to the mailing list, if preferred.

Setting up for development

Development Toolchain

stratisd can be built using a range of Rust toolchain versions. The recommended development toolchain usually tracks the Rust stable version, although it may lag it slightly. stratisd is guaranteed to be able to be built on its lowest supported toolchain, which may lag the recommended development toolchain by a few minor versions.

Contributors should use the recommended development toolchain if possible, since the CI makes use of the Rust linter and formatter for that version. The recommended development toolchain version can be determined by inspecting the CI configuration files for the project.

Building

Stratisd requires Rust and Cargo to build. These may be available via your distribution's package manager. If not, Rustup is available to install and update the Rust toolchain. Once toolchain and other dependencies are in place, run make build to build, and then run the stratisd executable as root.

Building tests

The Makefile provides a target, build-tests which allows compiling the tests without running any of them, as a convenience to developers.

Secondary dependencies

The Stratis ci repo includes a script, dependencies_fedora.sh, which installs all the development dependencies for stratisd and its CLI on Fedora.

Formatting

Stratisd makes use of rustfmt to enforce consistent formatting in Rust files. PRs must pass the fmt task in the CI in order to be merged. Run make fmt to ensure your changes conform to the expected formatting before submitting a pull request. Formatting changes a bit with different versions of the compiler; make sure to use the current development version.

Linting

Stratisd makes use of clippy to detect Rust lints. PRs must pass the clippy task in the CI in order to be merged. To check for lints, run make clippy. The lints change a bit with different versions of the compiler; make sure to use the current development version.

Configuring

Stratisd runs as root, and requires access to the D-Bus system bus. Thus in order to work properly, a D-Bus conf file must exist to grant access, either installed by distribution packaging; or manually, by copying stratisd.conf to /etc/dbus-1/system.d/.

Setting Log Levels

The command-line option, --log-level, may be used to set the stratisd log level. This option sets the level for the stratisd components only.

For finer-grained control over the log level of any stratisd component or dependency use the RUST_LOG environment variable. Please consult the documentation for the env_logger crate for additional information on the use of RUST_LOG.

Testing

Stratisd is tested in two ways. The first way makes use of the Rust test infrastructure and has more access to stratisd internals. The second way makes use of the stratisd D-Bus interface.

Tests that make use of the Rust test infrastructure

Stratisd incorporates two testing modalities:

• safe unit tests, which can be run without affecting your storage configuration
• unsafe unit tests, which may create and destroy devices during execution

To run the safe unit tests:

$ make test

For a description of the unsafe unit tests, necessary setup steps, and how to run them, see README_tests.md.

Test that interact with stratisd via the D-Bus

For a description of the D-Bus-based tests see tests/client-dbus/README.rst.

Allowed Bugs

stratisd has some bugs; most of these we intend to address in due course.

There is one bug that we have chosen not to fix. This is a bug in our D-Bus layer that will allow incorrect un-marshalling of certain D-Bus values if a D-Bus method is invoked with arguments that do not conform to the expected signature of the method. See the GitHub issue for additional details about this bug. Behavior of stratisd is undefined if a method is called under the particular circumstances that allow the bug to manifest.

Licensing

MPL 2.0. All contributions retain ownership by their original author, but must also be licensed under the MPL 2.0 to be merged.